Sheet transporting apparatus, and document reading apparatus and printing apparatus provided with the same

ABSTRACT

A sheet transporting apparatus including: sheet sensors arranged in a sheet transporting path; an enclosure door; a door sensor that detects the open/close state of the enclosure door; a control unit that determines the opened state or closed state of the enclosure door on the basis of the result of the detection by the door sensor, and makes a determination whether or not a sheet stays at the respective portions of the sheet sensors and whether or not the staying sheet is removed; and a display unit that displays a portion where the sheet stays, wherein the control unit controls such that it repeatedly makes a determination regarding the stay and the removal of the sheet when the sheet stays in the sheet transporting path and the enclosure door is opened, and updates the display on the basis of the result of the determination.

CROSS-REFERENCE TO RELATED APPLICATION

This application is related to Japanese Patent Application No. 2007-270406 filed on Oct. 17, 2007, whose priority is claimed and the disclosure of which is incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the invention

The present invention relates to a sheet transporting apparatus that detects a stay of a sheet in a sheet transporting path and removal of this sheet, and displays the portion where the sheet stays on a display unit, and a document reading apparatus and a printing apparatus provided with the same.

2. Description of the Related Art

There have been known document reading apparatuses provided with a document transporting apparatus for transporting a sheet-type document to a reading unit. The document reading apparatus provided with the document transporting apparatus is widely received in a market since it can save processing time and labor for reading plural documents at a time. There have been known printing apparatuses that can transport plural printing sheets one by one for printing. The printing apparatus described above has widely been received by the market since a user does not need to set a printing sheet one by one to a sheet feed section upon printing a printed matter composed of plural pages or plural printings.

When a document or one printing sheet (hereinafter referred to as a sheet) transported in a sheet transporting path is jammed in the apparatus (sheet transporting apparatus) having a function of transporting a sheet as described above, the next sheet has to be stopped in the transporting path. Therefore, sheets stay in various positions in the sheet transporting path. When the jamming occurs, the sheet transporting apparatus detects the occurrence of the jamming, stops the transportation of the sheet, and informs a user of the occurrence of the jamming with a display or an alarm sound. The sheet transporting apparatus not only displays the occurrence of the jamming but also displays the portion where the sheet stays on the display unit (display of a jam map) on the basis of the result of the detection of a sheet sensor arranged at each portion in the sheet transporting path. This is for reporting the user where to access for removing the sheet. The user recognizing the occurrence of the jamming opens a door (enclosure door) provided at an enclosure section of the sheet transporting apparatus, and removes the sheet staying at each portion in the sheet transporting path as referring to the displayed jam map. When the user operates a predetermined reset switch or closes the enclosure door after the sheets are removed, the sheet transporting apparatus checks whether or not a sheet still remains in the sheet transporting path in response to the aforesaid operation. When there is no sheet left behind in the sheet transporting path, the sheet transporting apparatus restarts the operation. However, any one of the sheet sensors detects a sheet, the sheet transporting apparatus updates the jam map in accordance with the result of the detection so as to inform the user of the sheet left behind in the sheet transporting path. When the reset switch is operated or the enclosure door is closed after all the remaining sheets are removed, the sheet transporting apparatus restarts the operation.

Recently, a highly functional sheet transporting apparatus provided with plural sheet feed sections or a reverse path for reading a double-sided document or for performing a double-sided printing is commercially available. As the function is enhanced, the sheet transporting path tends to be long and complicated. With this, the possibility of a user forgetting to take out a sheet tends to be high. In view of this, a design that makes it difficult for a user to forget to take out a sheet has been proposed. For example, an apparatus has been proposed (e.g., see Patent Document 1: Japanese Unexamined Patent Application No. H10-297795) in which a portion from which a user is likely to forget to take out a sheet is reported to the user for preventing the user from forgetting to take out the remaining sheet, and the position of the remaining sheet is displayed in a display manner according to the number of times in the past in which the user forges to take out the sheet at each position where the sheet remains, in order to save the complicated and repeated labor for the removing operation. For example, lighting/flickering display is made according to the number of times of the user forgetting to take out a sheet, the display is made with a different color according to the number of times of the user forgetting to take out a sheet, the display is made with a different size according to the number of times of the user forgetting to take out a sheet, or the display is made with a different pattern according to the number of times of the user forgetting to take out a sheet.

In the conventional sheet transporting apparatus, when a reset switch is depressed, or when an enclosure door is closed after a jamming process, new information is acquired from a sheet sensor arranged in a sheet transporting path, whereby a display content of a jam map is updated. In the apparatus described above, the jam map is updated only after the reset switch is depressed, or after the enclosure door is closed, even with a state in which a user forgets to take out a sheet from the sheet transporting path. Since the jam map is not repeatedly updated during the sheet removing operation, it can be said that the display is unkind to an inexperienced user.

SUMMARY OF THE INVENTION

The present invention is accomplished in view of the above-mentioned circumstance, and aims to provide a sheet transporting apparatus that can repeatedly detect a status of a sheet transporting path and can report the detected status to a user even during when a user performs a sheet removing operation.

The present invention provides a sheet transporting apparatus including: sheet sensors arranged at plural portions in a sheet transporting path, through which a sheet is transported, for detecting a sheet at the respective portions; an enclosure door that shields the sheet transporting path from the outside with the closed state thereof, and can be opened for removing a sheet when the sheet stays in the sheet transporting path; a door sensor that detects the open/close state of the enclosure door; a control unit that determines the opened state or closed state of the enclosure door on the basis of the result of the detection by the door sensor, and makes a determination as to whether or not a sheet stays at the respective portions and whether or not the staying sheet is removed; and a display unit that displays a portion where the sheet stays, when it is determined that the sheet stays in the sheet transporting path, wherein the control unit controls such that it repeatedly makes a determination regarding the stay and the removal of the sheet when the sheet stays in the sheet transporting path and the enclosure door is opened, and updates the display of the portion where the sheet stays on the basis of the result of the determination.

Further, the present invention provides a document reading apparatus provided with the sheet transporting apparatus.

Moreover, the present invention provides a printing apparatus provided with the sheet transporting apparatus.

In the sheet transporting apparatus, the control unit repeatedly makes a determination as to a stay and removal of a sheet when a sheet stays and the enclosure door is opened, and controls so as to update a display of the portion where the sheet stays on the basis of the result of the determination. Therefore, the sheet transporting apparatus can repeatedly detect the status of the sheet transporting path and can report the detected status to a user even during when the user performs a sheet removing operation.

In the present invention, the enclosure door means the respective doors mounted to the enclosure section for removing the sheet staying in the sheet transporting path. The door may be a revolving door having a hinge, or a drawout type door. Any type of the mechanism thereof may be employed if it is openable and closable. Further, no special limitations are imposed on the position and shape thereof.

The preferable embodiments of the present invention will be described below.

The apparatus may further include an opening mechanism that can open and close a part of the sheet transporting path for removing the staying sheet, and an opening portion sheet sensor that is arranged at a openable portion where the sheet transporting path is opened by the opening mechanism, and can detect the sheet when the openable portion is closed, the control unit may control such that it repeatedly makes a determination regarding the stay and the removal of the sheet at the openable portion on the basis of the result of the detection by the opening portion sheet sensor when the openable portion is closed, and updates the display of the portion where the sheet stays on the basis of the result of the determination, while the control unit may control such that it does not make a determination regarding the stay and the removal of the sheet and does not update the display when the openable portion is opened. With this, as to the result of the detection by the opening section sheet sensor, the control unit detects the status of the sheet transporting path at this portion and can report the detected status to a user, when the opening mechanism is closed.

The opening mechanism may further include an opening mechanism sensor that detects whether the opening mechanism is in its opened state or in its closed state, wherein the control unit may determine whether it makes a determination regarding the stay and the removal of the sheet at the openable portion and whether it updates the display based on the result of the determination on the basis of the result of the detection by the opening mechanism sensor. With this, the control unit can detect that the opening mechanism is closed on the basis of the result of the detection by the opening mechanism sensor, and can detect the status of the sheet transporting path with this detection.

The sheet transporting apparatus may further comprise an instruction section that allows a user to make an instruction, wherein the control unit may update the display on the display unit when the instruction is given. By virtue of this, the display is updated on receipt of the instruction from the user. Therefore, the user can easily recognize the status change before and after the instruction.

The control unit may accept the instruction only when the display unit displays the portion where a sheet stays. By virtue of this, the portion where the sheet stays is always displayed when the user gives an instruction. Therefore, the user can surely recognize the status change before and after the instruction.

The control unit may allow the display unit to display in a different manner a portion where a sheet stays and a portion where a sheet has been removed, when a sheet stays at plural portions. By virtue of this, the user can easily recognize the portion where the sheet is removed.

The control unit may make it possible to transport a sheet at the timing when the enclosure door is closed.

Various preferable embodiments described above may be combined.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an explanatory view showing a display example of a jam map according to an embodiment of the present invention;

FIG. 2 is an explanatory view showing an overall configuration of the inside of a digital multifunction peripheral according to the present embodiment;

FIG. 3 is an explanatory view showing the state in which a transportation destination of a sheet is changed by plural branch claws in the digital multifunction periphery according to the present embodiment;

FIG. 4 is an explanatory view showing outer appearances of a first unit, which can be drawn from a main body of a printing unit, and a second unit in the digital multifunction periphery according to the present embodiment;

FIG. 5 is an explanatory view showing the state in which the first unit is drawn from the main body and the second unit is drawn from the first unit in the digital multifunction periphery according to the present embodiment;

FIG. 6 is a perspective view (corresponding to FIG. 4) showing the state in which the first unit is drawn from the main body in the digital multifunction periphery according to the present embodiment;

FIG. 7 is a perspective view showing the state in which the second unit 103 is drawn from the first unit in the digital multifunction periphery according to the present embodiment;

FIG. 8 is an explanatory view showing the positions of sheet sensors arranged along a sheet transporting path in the digital multifunction periphery according to the present embodiment;

FIG. 9 is an explanatory view showing a modification of a display screen of the jam map in FIG. 1;

FIG. 10 is an explanatory view showing a modification in which the display screen of the jam map is different from that in FIG. 1;

FIGS. 11A and 11B are first and second explanatory views showing the detail of a procedure for removing a sheet staying in the sheet transporting path in the digital multifunction periphery according to the present embodiment;

FIGS. 12A and 12B are third and fourth explanatory views showing the detail of a procedure for removing a sheet staying in the sheet transporting path in the digital multifunction periphery according to the present embodiment;

FIG. 13 is a fifth explanatory view showing the detail of a procedure for removing a sheet staying in the sheet transporting path in the digital multifunction periphery according to the present embodiment; and

FIG. 14 is a sixth explanatory view showing the detail of a procedure for removing a sheet staying in the sheet transporting path in the digital multifunction periphery according to the present embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will be described in more detail below with reference to the drawings. It should be understood that the following description is illustrative of the invention in all aspects, but not limitative of the invention.

<Configuration of Sheet Transporting Path>

Firstly, a configuration of a sheet transporting path of an electrophotographic digital multifunction peripheral will be explained as one example of a sheet transporting apparatus according to the present invention. FIG. 2 is an explanatory view showing an overall configuration of the inside of the digital multifunction peripheral 11 according to the present embodiment. The digital multifunction peripheral shown in FIG. 2 includes a document reading unit 3 and a printing unit 1. The document reading unit 3 has a document transporting apparatus 5. The printing unit 1 forms an image onto a printing sheet in accordance with a document image read by the document reading unit 3 or print data received from an external device through a communication line. This corresponds to the aforesaid printing apparatus. Here, the sheet transporting path of the printing unit 1 will be explained.

As shown in FIG. 2, the printing unit 1 has, around a photosensitive drum 17 for forming an image by an electrophotographic process, a charger 19, an exposure unit 13, a developing device 15, a transfer mechanism (in the present apparatus, a transfer belt unit having a transfer belt 45) 39, and a cleaner unit 21. Further, the printing unit 1 includes a sheet feed tray 25, a sheet-feed-side sheet transporting path 27, a registration roller 29, a discharge-side sheet transporting path 31, a fixing unit 23, and a sheet exit tray 33. The transfer belt unit 39 transfers the toner image, formed on the surface of the photosensitive drum 17, onto a sheet.

The sheet feed tray 25 accumulates printing sheets. The sheet feed tray 25 is arranged below an image forming unit, and at the side wall face in the present apparatus. Plural sheet feed trays 25 arranged below the image forming unit include trays 1 and 2, which are arranged side by side, at the uppermost stage. The left one is the tray 1, while the right one is the tray 2. A tray 3 is arranged below the trays 1 and 2, and a tray 4 is arranged below the tray 3. On the other hand, a large-capacity sheet feed tray 73 that can store 4000 sheets and a manual tray 75 used for printing on a sheet of a non-standard size are arranged at the right side of the apparatus.

The registration roller 29 temporarily stops the sheet before the transfer belt unit 39 so as to be synchronous with the toner image transferred onto the sheet. The sheet-feed-side transporting path 27 extends upward from each of the sheet feed trays 25 to reach the registration roller 29. The discharge-side transporting path 31 is a path reaching a sheet exit roller 95 arranged at the outlet port to the sheet exit tray 33 through the registration roller 29, the transfer belt 45 and the fixing unit 23. When the sheet passes the transfer belt 45, the toner image formed onto the surface of the photosensitive drum 17 is transferred onto the sheet as described above. The sheet-feed-side transporting path 27 and the discharge-side transporting path 31 correspond to the sheet transporting path according to the present invention. Although not shown in FIG. 2, a sheet sensor for detecting a sheet is arranged in the sheet-feed-side transporting path 27 and the discharge-side transporting path 31.

A branch claw 77 is arranged in the discharge-side transporting path 31 over the fixing unit 23. By virtue of the branch claw 77, the sheet can be guided to a transporting path 81 (see FIG. 3) branched from the discharge-side transporting path 31. The transporting path 81 reaches a switchback unit 97 or the registration roller 29 through the portion where branch claws 83, 85 and 89 (see FIG. 3) are arranged. A transporting path 87 that guides the sheet to the sheet exit tray 33 from the switchback unit 97 is formed.

The image forming apparatus 11 has a control unit not shown. The control unit controls the operation of the image forming apparatus 11. The control unit is composed of, for example, a microcomputer, a ROM, a RAM, a non-volatile memory, an input circuit, an output circuit, and the like. The ROM stores a control program that is a procedure executed by the microcomputer. The RAM provides a work area to the microcomputer. The non-volatile memory backs up data necessary for the control and retains the same. Input signals from various sensors including the sheet sensor and switches are inputted to the input circuit. The output circuit includes a driver for driving various loads such as a drive motor for transporting a sheet and a solenoid for driving the branch claws.

FIG. 3 is an explanatory view showing the state in which the transporting destination of the sheet is switched by plural branch claws arranged in the vicinity of the inlet of the branched transporting path described above. The detail of the changeover of the discharge-side sheet transporting path 31 will be explained below with reference to FIG. 3.

As shown in FIG. 3, the branch claw 77 makes a changeover as to whether the sheet from the fixing unit 23 is transported to a transporting path 79, which constitutes a part of the discharge-side transporting path 31, or to the transporting path 81. Branch claws 83, 85, 89 and 92 are provided in the vicinity of the outlet of the transporting path 81. The branch claws 77, 83, 85 and 89 are movable, and biased in one direction (first position) by an elastic member. The branch claws 77, 85, and 89 can change their positions (second position) against the biasing force through the drive of the corresponding solenoids. The branch claw 92 is stationary. The microcomputer drives the solenoids corresponding to the branch claws 77, 85 and 89 so as to be capable of changing the position of each branch claw to the second position. The branch claw 85 can change its position to a third position by the microcomputer and the drive solenoid.

The branch claw 83 is weakly biased toward the first position by the elastic member. When the sheet abuts the branch claw 83 in case where the later-described branch claw 85 is in the second position, the branch claw 83 moves to the second position by the stiffness at the leading end of the sheet and the transporting force of a transport roller 93. However, the sheet conveyed from the reverse direction, i.e., from a transporting path 84, cannot enter the transporting path 81 because it is blocked by the branch claw 83.

The branch claw 85 allows the sheet, which is conveyed from the transporting path 81, to the transporting path 84 that reaches the registration roller 29 in cooperation with the branch claw 83 at the first position. Further, it guides the sheet to a transporting path 90 that reaches the switchback unit 97. It also guides the sheet from the transporting path 84 to the transporting path 87 that reaches the sheet exit tray 33.

The branch claw 89 guides, at the first position, the sheet from the switchback unit 97 to the transporting path 87 that reaches the sheet exit tray 33. Further, it guides, at the second position, the sheet to the transporting path 84 that reaches the registration roller 29.

The microcomputer controls the transportation of the sheet as described below in accordance with the instructed printing condition.

1) Face-Up Discharge in One-Sided Printing

The microcomputer moves the branch claw 77 to the first position so as to guide the transported sheet to the transporting path 79 at the timing when the sheet, which passes the fixing unit 23, passes through the transport roller 93 at the latest. The sheet is discharged to the sheet exit tray 33 with a face-up state through the sheet exit roller 95.

2) Face-Down Discharge in One-Sided Printing

The microcomputer moves the branch claw 77 to the second position so as to guide the transported sheet to the transporting path 81 at the timing when the sheet, which passes the fixing unit 23, passes through the transport roller 93 at the latest. Further, the microcomputer moves the branch claw 85 to the first position. The leading end of the transported sheet is guided by the branch claw 77 to pass through the transporting path 81. The sheet further passes through the outlet of the transporting path 81 against the press-contact force by the branch claw 83 by the transporting force of the transport roller 93 and the stiffness at the leading end of the sheet, and reaches the branch claw 85. Thereafter, the leading end of the sheet is guided by the branch claw 85 to be directed to the transporting path 84. The microcomputer temporarily stops the transportation of the sheet at the timing when the trailing end of the sheet reaches the position of the branch claw 92. Then, the microcomputer changes the position of the branch claw 85 to the third position to open the transporting path 87 and to shield the transporting path 90. The branch claw 83 is biased by the elastic member to shield the transporting path 81 as described above. As described above, after the position of the branch claw 85 is changed, the microcomputer inversely rotates an inverse transport roller 94 so as to transport the sheet in the direction reverse to the entering direction. The sheet passes through the transporting path 87 with the side thereof close to the branch claw 90, i.e., the trailing end of the sheet when it enters the transporting path 84, defined as the leading end, and is discharged to the sheet exit tray 33 through the sheet exit roller 95.

3) Double-Sided Printing

The microcomputer moves the branch claw 77 to the second position so as to open the transporting path 81 and shield the transporting path 79 at the timing when an image is transferred onto a first face (front surface) and the sheet passing through the fixing unit 23 passes through the transport roller 93 at the latest. Further, it moves the branch claw 85 to the second position so as to open the transporting path 90 and shield the transporting path 84. The microcomputer also changes the position of the branch claw 89 so as to open the transporting paths 91 and 87 and shield the transporting path 84. Further, the microcomputer changes the position of the branch claw 89 so as to open the transporting paths 91 and 87 and shield the transporting path 84. The leading end of the sheet is guided by the branch claw 77 to pass through the transporting path 81. After the sheet passes through the branch claw 83 by the stiffness of the leading end of the sheet and the transporting force of the transport roller 93, the sheet is guided by the branch claw 85 to pass through the transporting path 90 and be directed to the transporting path 91. The microcomputer temporarily stops the transportation of the sheet at the timing when the trailing end of the sheet reaches the transporting path 91 (the switchback of the first face is completed). Then, the microcomputer changes the branch claw 89 to the second position to shield the transporting path 90 and open the transporting path 84. Thereafter, the microcomputer inversely rotates a switchback roller 96, thereby transporting the sheet in the direction reverse to the advancing direction to the switchback unit 97. The sheet passes through the branch claws 89 and 92 and is directed to the transporting path 84 with the trailing end of the sheet when it enters the transporting path 91 defined as the leading end. Then, the sheet is transported to the registration roller 29. Further, the sheet is transported on the transfer belt 45 in synchronism with the image on the second face. When the image on the second face (back surface) is transferred onto the sheet and the sheet passes through the fixing unit 23, the microcomputer moves the branch claw 77 to the first position at the timing when the sheet passes through the transport roller 93 at the latest. The transported sheet is discharged to the sheet exit tray 33 through the transporting path 79 and the sheet exit roller 95.

<Removal Method of Staying Sheet>

Explained next is the mechanism and procedure for removing a sheet staying in the sheet transporting path by a user when a jamming occurs at the printing unit 1 having the sheet transporting path. The printing unit 1 has a mechanism of opening the sheet transporting path so as to make it easy to remove the sheet by the user when a jamming occurs. More specifically, the printing unit 1 is configured in a unit such that most part of the sheet transporting path can be drawn in the near direction. The user can draw the unit and access to the sheet transporting path after the user opens a front door of an enclosure unit not shown. Instead of the front door, a door may be provided to the side section.

FIG. 4 is an explanatory view showing outer appearances of a first unit 101 and a second unit 103 that are units drawable from the printing unit 1. Guide rails 98 and 99 are mounted to the main body of the printing unit 1. The first unit 101 is mounted to the main body through the guide rails 98 and 99. The second unit is mounted to the first unit 101 through an unillustrated guide rail. FIG. 4 shows the state in which the first unit 101 and the second unit 103 are housed in the main body of the printing unit 1. The sheet is transported in the sheet transporting path with this state. For easy understanding, the first unit 101 and the second unit 103 are indicated by a bold solid line.

A part of the sheet-feed-side transporting path 27 and the discharge-side sheet transporting path 31 are positioned at the upper part of the first unit 101. When the first unit 101 is drawn from the main body, they are exposed. The user can easily remove the sheet staying at the exposed portion with this state.

FIG. 5 is an explanatory view showing the state in which the first unit 101 is drawn from the main body and the second unit 103 is drawn in the left direction from the first unit 101. With this state, the transporting path 79 is exposed at the upper part at the side of the sheet exit tray 33 of the second unit 103, the transporting path 81 is exposed at the upper sheet-feed side, and the transporting path 87 and the transporting path 90 are exposed at the upper discharge side. Further, when the second unit 103 is drawn from the first unit 101, the transporting path 84, the transporting path from the inverse transport roller 94 to the registration roller 29, the transporting path 91, and the switchback unit 97 are exposed. The transporting path 84 is at the upper part of the second unit 103, and the transporting path 91 and the switchback unit 97 are at the lower part. As described above, the user can easily remove the sheet staying in the transporting paths 79, 81, 84, 87, 90 and 91, the transporting path from the inverse transport roller 94 to the registration roller 29, and the switchback unit 97 with the second unit 103 drawn from the first unit 101.

FIG. 6 is the state corresponding to FIG. 4, and is a perspective view showing the state in which the first unit 101 is drawn from the main body. As shown in FIG. 6, a part of the sheet-feed-side transporting path 27 and the sheet transporting path 31 are exposed at the upper part of the first unit 101.

FIG. 7 is a perspective view showing the state in which the second unit 103 is drawn from the first unit 101 from the state in FIG. 6. FIG. 7 corresponds to FIG. 5. Although the detail of the transporting paths is omitted in FIG. 7, the transporting path 84 and the transporting path from the inverse transport roller 94 to the registration roller 29, which are hidden below the first unit 101, are exposed, and the transporting path 81, which is hidden because it is sandwiched between the first unit 101 and the second unit 103, is exposed, when the second unit 103 is drawn. The transporting path 79 is exposed at the upper part of the second unit 103, and the transporting paths 87 and 90 are exposed at the side of the sheet exit tray 33 of the second unit 103. The switchback unit 97 and the transporting path 91 are positioned at the lower part of the second unit 103, but a user turns a switchback roller 96 disposed in the transporting path 91 so as to easily remove the sheet staying in the transporting path 91 and the switchback unit.

<Arrangement of Sheet Sensor and Display of Jam Map>

An arrangement example of the sheet sensor according to the present invention will be described. FIG. 8 is an explanatory view showing the positions of sheet sensors arranged along the sheet transporting path in the printing unit 1. The configuration of the sheet transporting path corresponds to the printing unit 1 in FIG. 2. Among the sheet sensors shown in FIG. 8, sheet sensors SS01 to 07 are arranged at the main body of the printing unit. Sheet sensors SS11 to 14 are arranged at the first unit 101. Sheet sensors SS21 to 26 are arranged at the second unit 103. Each of the sheet sensors is a reflective-type photointerrupter. Alternatively, it may be a combination of a transmission photointerrupter and a cantilever. It is well known that these are used for the detection of a sheet.

When these sheet sensors detect jamming, the microcomputer causes an operation panel section (not shown) of the digital multifunction peripheral 11 to display a jam map. FIG. 1 is an explanatory view showing an example of the display of the jam map according to the present embodiment. The marks ▾ having a shape of rotated triangle in FIG. 1 correspond to the sheet sensors, and these marks are displays for indicating a position where a sheet stays (jammed-position display). For example, a jammed-position J01 is displayed when the sheet sensor SS01 detects a stay of a sheet. The jammed-position displays J02 to J07 correspond to the sheet sensors S02 to 07 respectively. There are displays corresponding to the sheet sensors SS11 to 14 and S21 to 26, but the numerals are omitted, except for some ones, because the figure becomes complicated.

Although the jammed-position displays corresponding to the sheet sensors SS01 to 07, SS11 to 14 and SS21 to 26 are illustrated in FIG. 1 for illustration, only the position where a sheet stays is generally displayed. For example, when a sheet is fed from the lowermost sheet feed tray, the displays of J02, J04, J05, J06 and J07 corresponding to the sheet feed sections other than the lowermost sheet feed tray are not displayed. When plural sheets stay in the sheet transporting path, the jammed-position displays corresponding to the portions where sheets stay are displayed. It is well known that the position of the staying sheet in the sheet transporting path is displayed onto the jam map according to the result of the detection of each sheet sensor.

<Update of Jammed-Position Display During Removal Operation of Sheet>

Next, a technique of updating the content of the jammed-position display according to the status of the operation for removing a sheet by a user will be explained. This is the characteristic point of the present invention.

In the digital multifunction peripheral 11 according to the present embodiment, a power source and signal wirings are configured such that, even with the state in which a user opens an enclosure door for removing a sheet staying in the sheet transporting path of the printing unit 1, power supply is applied to each sheet sensor so as to detect the presence or absence of the sheet. The signal from each sheet sensor is directed to the input circuit, whereby the microcomputer serving as a control unit can read the result of the detection by each sheet sensor. The wirings are configured such that power supply is fed to the main body of the printing unit and the sheet sensors SS11 to 14 and SS21 to 26 arranged at the first and the second units with the first unit 101 drawn by a user, and the microcomputer can read the result of the detection of each sheet sensor. For example, a bent beam is bridged between a frame section at the far side (not shown) of the main body of the printing unit and the frame at the far side of the first unit 101, wherein the power source and signal wiring of each sheet sensor are hung down to form a wiring arch. The wirings are configured such that power supply is fed to the sheet sensors SS21 to 26 arranged at the second unit with the second unit 103 drawn from the first unit 101 by a user, and the microcomputer can read the result of the detection of each sheet sensor. For example, a bent beam is bridged between the first unit and the second unit, wherein the power source and signal wiring of each sheet sensor are hung down to form a wiring arch. The beam is preferably mounted at the position indicated by a chain line of 105 in FIG. 5.

In order to remove the staying sheet, the digital multifunction peripheral 11 is provided with the portion where an opening mechanism for opening the transporting path in the vicinity of the portion where the sheet stays and a portion where a knob or the like is provided for manually transporting the sheet in the vicinity of the portion where the sheet stays, as described later, wherein a user turns the knob for moving the staying sheet.

As for the portion where the user turns the knob to move the sheet to the open end of the sheet transporting path in order to remove the sheet, the microcomputer always reads the signal from the sheet sensor arranged at this portion. The microcomputer continues to monitor the status as to whether the sheet stays or is removed, and updates the display of the jam map. In this case, in order to prevent the erroneous detection of noise superimposed on the signal from the sensor, it is preferable that the microcomputer samples the output from the sensor at an interval of about 50 to 100 ms, and when the results of the sampling agree with each other five times to ten times in succession, this state is adopted as the result of the detection. By virtue of this, the noise from the electrical noise having relatively short cycle such as a jitter to the noise having relatively long cycle such as a mechanical bounce from an actuator can be eliminated, whereby a stable detection can be carried out.

On the other hand, as for the portion where the opening mechanism is provided, and the staying sheet is removed after the sheet transporting path in the vicinity of the portion where the sheet stays is opened by the user, it is difficult to correctly detect the sheet by the sheet sensor with the sheet transporting path opened, because of its mechanical structure. In view of this, the microcomputer stops the reading of the signal from the sheet sensor when the sheet transporting path is opened. When the sheet transporting path is closed, the microcomputer samples the signal from the sheet sensor. Therefore, a sensor for detecting the open/close state is provided to the opening mechanism. It is preferable that the signal is sampled at an interval of about 50 to 100 ms, and when the results of the sampling agree with each other five times to ten times in succession, this state is adopted as the result of the detection from the viewpoint of achieving the stable detection.

By virtue of this, the display of the jam map is not updated with the sheet transporting path at the portion where the user removes the sheet opened. However, when the sheet transporting path at this portion is closed, the display of the jam map is updated. Therefore, compared to the case in which the jam map is updated only after the sheet at the other portions is removed and the front door is closed, the display of the jam map is updated, which is effective for preventing the user from forgetting to take out the sheet. That is, when another sheet stays at the portion where the sheet removing operation is carried out, the display of the jam map remains at the time when the sheet transporting path at this portion is closed, so that the user confirming the display recognizes that he/she forgets to take out the sheet.

For example, it is supposed that a sheet that a user forgets to take out is present at the second unit 103. In the conventional case, it is after the second unit 103 is inserted in the first unit 101, the first unit 101 is inserted in the main body of the printing unit, and the front door is closed when the user recognizes that he/she forgets to take out the sheet. It is because, since the display of the jam map is not updated until the front door is closed, the condition of the staying sheet is not correctly displayed. In this case, the user should open the front door again, draw the first unit 101, draw the second unit 103 to remove the sheet, which is left behind, then insert the second unit 103, insert the first unit 101, close the front door, and confirm whether the redoing operation is well done or not. On the other hand, according to the present embodiment, after the sheet is correctly removed, the jammed-position display of the corresponding portion is turned off at the time when the sheet transporting path is closed. The user confirms the jammed-position displays after carrying out the removing operation at each jammed position, and can recognize that there is no sheet left behind. Accordingly, even if there is a sheet that is left behind, the user can easily remove the sheet again. The present invention can remarkably enhance the convenience of a user involved with the sheet removing operation.

FIG. 9 is an explanatory view showing a modification of the screen of the display of the jam map in FIG. 1. The modification is different from the display screen of the jam map in FIG. 1 in that an “update” button B1 is added. In FIG. 9, it is the presumption that the display section has a touch panel. Therefore, when the user touches the “update” button, the microcomputer can read this state. In the modification, the microcomputer continuously monitors the status of each sheet sensor like the embodiment described above. However, different from the embodiment described above, it does not continuously update the display screen of the jam map. Instead of this, the display of the jam map is updated when the “update” button B1 is depressed. With this structure, the user can recognize the status change only when he/she updates the display of the jam map according to his/her wish. There is a viewpoint that the user more easily recognizes the status change in the modification than in the aforesaid embodiment in which the display of the jam map is updated during the sheet removing operation. However, the modification is poor in real time performance, since the display of the jam map is not updated until the user depresses the update button.

The microcomputer displays the “update” button B1 only on the display screen of the jam map. Therefore, when the user depresses the “update” button B1, the user can surely recognize the change between the status of the staying sheet before the update and the status of the staying sheet after the update.

FIG. 10 is an explanatory view showing a modification in which the display screen of the jam map is different from that in FIG. 1. In the example in FIG. 10, the portion where a sheet stays is indicated by ▾ mark when jamming occurs. After the sheet is removed, the jammed-position display is not turned off but the mark indicating the jammed-position display is changed to  mark. In FIG. 10, the jammed-position displays J12, J13 and J26 are indicated by  mark. This shows that a sheet staying at the portion where the sheet sensors SS12, SS13 and SS26 are arranged is removed. On the other hand, the jammed-position displays J01, J03, or the like are indicated by ▾ mark. This shows that a sheet still stays at the portion corresponding to these jammed positions. By virtue of this, the user can exactly grasp the portion where the sheet has already been removed. The display manner for the removed sheet is not limited to the  mark. The display manner can be changed, for example, such that the other mark such as □ mark is employed, the status is distinguished by a lighting display and flickering display, a color is made different, or the size of the jammed-position display is made different.

<Detail of Removal Procedure of Staying Sheet>

FIGS. 11 to 14 are explanatory views for showing the detail of the procedure for removing a staying sheet in the sheet transporting path of the printing unit 1. FIGS. 11 to 13 show the procedure for removing a sheet staying in the first unit 101 and the second unit 103. FIG. 14 shows the procedure for removing a sheet staying in the longitudinal transporting path of the sheet-feed-side transporting path 27.

Before a procedure 3 in FIG. 11A, there are a procedure 1 for releasing the lock of the front door of the enclosure section and a procedure 2 for opening the front door, but these procedures are not illustrated. In the procedure 3, a drawing lever is turned to bring the first unit 101 in the drawable state, and in the procedure 4, the first unit 101 (including the second unit 103) is drawn in the near direction and locked. In a procedure 5, if there is a sheet detected by the sheet sensor SS07, the user removes this sheet. The microcomputer continuously reads the sheet sensor SS07. After the sheet is removed, the microcomputer turns off the jammed-position display J07 corresponding to the removed sheet.

When there is a sheet that is conveyed from the sheet feed tray 25 and detected by the sheet sensor SS11 in the procedures 6 and 7 in FIG. 11B, the user turns the knob to remove this sheet. The microcomputer continuously reads the sheet sensor SS11. After the sheet is removed, the microcomputer turns off the jammed-position display J11 corresponding to the removed sheet. When there is a sheet that is conveyed from the manual tray 75 and detected by the sheet sensor SS11 in the procedures 8 and 9, the user lays down a paper guide to open the sheet transporting path, and removes the sheet. The collapsible paper guide corresponds to the opening mechanism. The microcomputer discontinues the reading of the sheet sensor SS11 during when the paper guide is opened, and restarts the reading after the paper guide is closed. If the sheet is removed when the paper guide is closed, the microcomputer turns off the jammed-position display J11.

When there is a sheet detected by the sheet sensor SS12 in procedures 10 and 11 in FIG. 12A, the user lays down the paper guide to open the sheet transporting path, and removes the sheet. The collapsible paper guide corresponds to the opening mechanism. The microcomputer discontinues the reading of the sheet sensor SS12 during when the paper guide is opened, and restarts the reading after the paper guide is closed. If the sheet is removed when the paper guide is closed, the microcomputer turns off the jammed-position display (the mark is not shown in FIG. 1).

Next, the user draws the second unit 103 in the procedure 12. When there is a sheet detected by the sheet sensor SS14 in procedure 13 and procedure 14 in FIG. 12B, the user turns the knob to remove this sheet. The microcomputer continuously reads the sheet sensor SS11. When the sheet is removed, the microcomputer turns off the jammed-position display (the mark is not shown in FIG. 1) corresponding to the sheet sensor SS11.

When there is a sheet detected by the sheet sensor SS26 in procedures 15 and 16, the user lifts up the paper guide to open the sheet transporting path at this portion, and removes the sheet. The movable paper guide corresponds to the opening mechanism. The microcomputer discontinues the reading of the sheet sensor SS26 during when the paper guide is opened, and restarts the reading after the paper guide is closed. If the sheet is removed when the paper guide is closed, the microcomputer turns off the jammed-position display J26 corresponding to the sheet sensor SS26.

When there is a sheet detected by the sheet sensor SS25 in procedures 17 and 18, the user opens the paper guide to open the sheet transporting path at this portion, and removes the sheet. The movable paper guide corresponds to the opening mechanism. The microcomputer discontinues the reading of the sheet sensor SS25 during when the paper guide is opened, and restarts the reading after the paper guide is closed. If the sheet is removed when the paper guide is closed, the microcomputer turns off the jammed-position display (the mark is not shown in FIG. 1) corresponding to the sheet sensor SS25.

When there is a sheet detected by the sheet sensor SS23 and/or the sheet sensor SS23 in procedures 19 and 20 in FIG. 13, the user lifts up the paper guide to open the sheet transporting path at this portion, and removes the sheet. The movable paper guide corresponds to the opening mechanism. The microcomputer discontinues the reading of the sheet sensors SS22 and SS23 during when the paper guide is opened, and restarts the reading after the paper guide is closed. If the sheet is removed when the paper guide is closed, the microcomputer turns off the jammed-position displays (the numerals are not shown in FIG. 1) corresponding to the sheet sensors SS22 and SS23.

When there is a sheet detected by the sheet sensor SS24 in procedures 21 and 22, the user lifts up the paper guide to open the sheet transporting path at this portion, and removes the sheet. The movable paper guide corresponds to the opening mechanism. The microcomputer discontinues the reading of the sheet sensor SS24 during when the paper guide is opened, and restarts the reading after the paper guide is closed. If the sheet is removed when the paper guide is closed, the microcomputer turns off the jammed-position display (the numeral is not shown in FIG. 1) corresponding to the sheet sensors SS24.

Subsequently, FIG. 14 will be explained. FIG. 14 is a procedure for removing the sheet staying in the longitudinal transporting path of the sheet-feed-side transporting path 27. The user opens the front door of the enclosure section in a procedure 1 in FIG. 14. When there is a sheet detected by the sheet sensor SS11 in a procedure 2, the user removes this sheet. The procedure for removing the sheet detected by the SS11 has already been explained in the procedures 6 and 7 in FIG. 11. When the drawing of the first unit 101 is preceding as the sheet removing operation, the sheet is removed in the procedures 6 and 7 in FIG. 11. When the confirmation of the longitudinal transporting path of the sheet-feed-side transporting path 27 is preceding, the sheet is removed in this procedure. After the sheet is removed, the microcomputer turns off the jammed-position display J11 corresponding to the sheet sensor SS11.

When there is a sheet detected by the sheet sensor SS03 in procedures 3 and 4, the user opens the paper guide to open the transporting path at this portion, and removes the sheet. The movable paper guide corresponds to the opening mechanism. The microcomputer discontinues the reading of the sheet sensor SS03 during when the paper guide is opened, and restarts the reading after the paper guide is closed. If the sheet is removed when the paper guide is closed, the microcomputer turns off the jammed-position display J03 corresponding to the sheet sensor SS03.

In the present embodiment, the case in which the jam map is displayed is taken as an example. However, instead of the jam map, a configuration in which a name or number for identifying each sheet sensor is displayed, or the configuration in which these are displayed as a message, can be employed, as a modification.

Various modifications are possible for the present invention in addition to the embodiment described above. It should be understood that such modifications also fall within the aspects and scope of the present invention. The present invention is intended to embrace all alterations made within the scope of the invention defined by the appended claims and their equivalents. 

1. A sheet transporting apparatus comprising: sheet sensors arranged at plural portions in a sheet transporting path, through which a sheet is transported, for detecting a sheet at the respective portions; an enclosure door that shields the sheet transporting path from the outside with the closed state thereof, and can be opened for removing a sheet when the sheet stays in the sheet transporting path; a door sensor that detects the open/close state of the enclosure door; a control unit that determines the opened state or closed state of the enclosure door on the basis of the result of the detection by the door sensor, and makes a determination as to whether or not a sheet stays at the respective portions and whether or not the staying sheet is removed; and a display unit that displays a portion where the sheet stays, when it is determined that the sheet stays in the sheet transporting path, wherein the control unit controls such that it repeatedly makes a determination regarding the stay and the removal of the sheet when the sheet stays in the sheet transporting path and the enclosure door is opened, and updates the display of the portion where the sheet stays on the basis of the result of the determination.
 2. The sheet transporting apparatus according to claim 1, further comprising an opening mechanism that can open and close a part of the sheet transporting path for removing the staying sheet, and an opening portion sheet sensor that is arranged at a openable portion where the sheet transporting path is opened by the opening mechanism, and can detect the sheet when the openable portion is closed, wherein the control unit controls such that it repeatedly makes a determination regarding the stay and the removal of the sheet at the openable portion on the basis of the result of the detection by the opening portion sheet sensor when the openable portion is closed, and updates the display of the portion where the sheet stays on the basis of the result of the determination, while the control unit controls such that it does not make a determination regarding the stay and the removal of the sheet and does not update the display when the openable portion is opened.
 3. The sheet transporting apparatus according to claim 2, wherein the opening mechanism further includes an opening mechanism sensor that detects whether the opening mechanism is in its opened state or in its closed state, wherein the control unit determines whether it makes a determination regarding the stay and the removal of the sheet at the openable portion and whether it updates the display based on the result of the determination on the basis of the result of the detection by the opening mechanism sensor.
 4. The sheet transporting apparatus according to claim 1, further comprising an instruction section that allows a user to make an instruction, wherein the control unit updates the display on the display unit when the instruction is given.
 5. The sheet transporting apparatus according to claim 4, wherein the control unit accepts the instruction only when the display unit displays the portion where a sheet stays.
 6. The sheet transporting apparatus according to claim 1, wherein the control unit allows the display unit to display in a different manner a portion where a sheet stays and a portion where a sheet has been removed, when a sheet stays at plural portions.
 7. The sheet transporting apparatus according to claim 1, wherein the control unit makes it possible to transport a sheet at the timing when the enclosure door is closed.
 8. A document reading apparatus provided with the sheet transporting apparatus according to claim
 1. 9. A printing apparatus provided with the sheet transporting apparatus according to claim
 1. 